Merge pull request #1703 from rpwoodbu/patch-3

Clarify array out-of-bounds behavior.

Author: marioidival

src/primitives/array.md

@@ -63,7 +63,9 @@ fn main() {
         }
     }
 
-    // Out of bound indexing causes compile time error.
+    // Out of bound indexing on array causes compile time error.
     //println!("{}", xs[5]);
+    // Out of bound indexing on slice causes runtime error.
+    //println!("{}", xs[..][5]);
 }
 ```